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A291976
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a(n) = (4*n)! * [z^(4*n)] exp(1 - (cos(z) + cosh(z))/2).
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4
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1, -1, 34, -5281, 2185429, -1854147586, 2755045819549, -6440372006517541, 21861211462545555394, -100916681831006840635021, 596756926975162013357972089, -4237398636260867429185819175026, 32919774165127854788267224335178009
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OFFSET
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0,3
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COMMENTS
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LINKS
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MAPLE
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A291976 := proc(n) exp(1 - (cos(z) + cosh(z))/2):
(4*n)!*coeff(series(%, z, 4*(n+1)), z, 4*n) end:
# second Maple program:
b:= proc(n, t) option remember; `if`(n=0, 1-2*t, add(
b(n-4*j, 1-t)*binomial(n-1, 4*j-1), j=1..n/4))
end:
a:= n-> b(4*n, 0):
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MATHEMATICA
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b[n_, t_] := b[n, t] = If[n == 0, 1-2t, Sum[b[n-4j, 1-t] * Binomial[n-1, 4j-1], {j, 1, n/4}]];
a[n_] := b[4n, 0];
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CROSSREFS
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KEYWORD
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sign
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AUTHOR
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STATUS
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approved
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